haloNodes(A, noElem)

function Anew = haloNodes(A, noElem)
% HALONODES returns a variant array containing localPart of the input
% distributed array and band of elements of thickness noElem from its left
% and right neighbors. 
%  
% This function currently works for 1D distributions of
% 2D arrays, takes a distributed array, returns the localPart plus
% overlapping (halo) nodes

distCheck = strcmp(class(A),'codistributed');

if distCheck
    % Getting distribution information
    distA = codistributor(A);
    dimA = distributionDimension(distA);
    sizeA = size(localPart(A));

    % Padding the size of A to include surrounding values
    sizeA(dimA) = sizeA(dimA) + noElem * 2;
    Anew = zeros(sizeA);

    % Setting the offset for each array part
    offset(1:2) = 0;
    offset(dimA) = noElem;

    % Creating local part of A and filling with values
    Anew(1+offset(1):offset(1)+size(localPart(A),1),1+offset(2):...
        offset(2)+size(localPart(A),2))...
        = localPart(A);

    % Getting the surrounding values (to the right) and putting into A
    if labindex < numlabs; labFrom = labindex + 1;
    else labFrom = 1; end;

    if labindex > 1; labTo = labindex - 1;
    else labTo = numlabs; end;

    myDataSize = sizeA;
    myDataSize(dimA) = noElem;

    myData = Anew(1+offset(1):offset(1)+myDataSize(1),...
        1+offset(2):offset(2)+myDataSize(2));

    haloData = labSendReceive(labTo, labFrom, myData);
    myReceiveSize = size(haloData);

    if ~isempty(haloData)
        Anew(end+1-myReceiveSize(1):end,end+1-myReceiveSize(2):end)=...
            haloData;
    end

    % Getting the surrounding values (to the left) and putting into A
    if labindex > 1; labFrom = labindex - 1;
    else labFrom = numlabs; end;

    if labindex < numlabs; labTo = labindex + 1;
    else labTo = 1; end;

    myDataSize = sizeA;
    myDataSize(dimA) = noElem;

    myData = Anew(end - myDataSize(1)+1-offset(1): end - offset(1), ...
        end - myDataSize(2) + 1 - offset(2):end - offset(2));

    haloData = labSendReceive(labTo, labFrom, myData);
    myReceiveSize = size(haloData);

    if ~isempty(haloData)
        Anew(1:myReceiveSize(1),1: myReceiveSize(2))=...
            haloData;
    end

else

    Anew = A;

end